1. Field of the Invention
The present invention relates to a semiconductor device and, more particularly, to a pre-driver circuit and an output circuit using the same.
2. Discussion of Related Art
A conventional data output circuit will be described with reference to FIG. 1, which shows a block diagram schematically illustrating the configuration of a data output circuit having a pre-driver circuit in a related art.
A data signal that is outputted as a logical High or a logical Low is inputted to an off-chip driver circuit 100 and a pre-driver circuit 200 and a data signal (Dout) is then outputted through an output driver circuit 300.
The off-chip driver circuit 100 includes off-chip drivers 100-1 to 100-N. The respective off-chip drivers 100-1 to 100-N use the same data signal as one input and corresponding first to Nth control signals as the other input. Each of the off-chip drivers 100-1 to 100-N functions to reflect a possible difference in the performance of devices according to process conditions performed. In the above, N is a natural number of 2 or more.
Meanwhile, each of the off-chip drivers of the off-chip driver circuit 100 is connected correspondingly to output drivers within the output driver circuit 300. If a corresponding off-chip driver is turned off, an output driver connected thereto is turned off, and if a corresponding off-chip driver is turned on, an output driver connected thereto is turned on.
The pre-driver circuit 200 receives the data signal (DATA) and then functions to pull up or pull down according to a logical level of the signal. The pre-driver circuit 200 drives a corresponding output driver within the output driver circuit 300.
If the off-chip driver circuit operates in a high frequency state, however, it is not technically easy for a waveform of each data signal that is outputted while passing through the pre-driver circuit to have an adequate slew rate. In particular, a difference in device characteristics depending on advanced process status makes controlling a slew rate at both conditions difficult. Accordingly, there is an urgent need to implement a circuit that can accomplish a stabilized operation at each data path, while satisfying a slew rate required by a system.